The protein 'Smac' (or Smac/Diablo) plays an important role in programmed cell death, (apoptosis) by down regulating the inhibitor of apoptosis (lAP) proteins, which are overexpressed in many cancers. [unreadable] [unreadable] The proposed studies first examine how Smac is mobilized within the death pathway under various death stimuli. Furthermore, we explore the utility of Smac small molecule peptide mimics for use in diagnostic imaging of cancers via novel molecular targeting. We also explore the use of Smac mimetics as general, small molecule as anticancer agents to avert, or kill tumor cells. [unreadable] [unreadable]